Until the Geneva patient, researchers believed that the CCR5 delta 32 mutation – known to make cells naturally resistant to HIV – was crucial to achieving lasting remission. But this Swiss case challenges previous theories about HIV remission. Indeed, this patient is the first in remission to have received a transplant from a donor who did not carry the famous mutation. The other five known to be in HIV remission all received bone marrow transplants carrying the protective mutation.
Professor Alexandra Calmy of the Geneva University Hospitals and Professor Asier Sáez-Cirión of the Pasteur Institute, coordinators of the study, emphasize the importance of this unique case. Despite the absence of the protective mutation, the virus remains undetectable in this patient, named Romuald, nearly three years after stopping antiretroviral treatment.
The researchers observed a progressive decrease in the viral reservoir following the transplant, with a disappearance of virus-carrying cells capable of multiplying.
How to explain it?
Although this case had already been reported in July 2023, scientists struggled to explain this exceptional remission. Today, several hypotheses are being put forward. The presence of innate immune cells with high anti-HIV potential could counter the possible rebound of the virus from the few infected cells that could remain in the body. “, explain the authors. ” Furthermore, the immunomodulatory treatment this patient is receiving to control the graft-versus-host reactions, repeatedly experienced since the transplant, could help prevent viral reactivation. Ultimately, these graft-versus-host reactions may have led to such effective elimination of the viral reservoir that the CCR5 delta 32 mutation is no longer necessary because no virus capable of multiplying would remain in the body. »
This discovery opens new perspectives in HIV remission research. It suggests that other mechanisms, beyond the CCR5 delta 32 mutation, may lead to durable remission.
